Adjustable supporting leg



Nov. 18, 1952 w. J. s. JOHNSON 2,618,496

ADJUSTABLE SUPPORTING LEG Filed Sept. l5. 1947 1N V EN TOR. MAL/aci .5.Ja//Nw/v Patented Nov. 18, 1952 UNITED STATES PATENT OFFICEv ADJUSTABLESUPPORTING LEG Wallace J. S. Johnson, Berkeley, Calif.

Application September 15, 1947, Serial No. 774,036

1 Claim. 1

The present invention relates to a leg construction, and moreparticularly to an adjustable supporting leg adapted to form part of ascaiold, hospital bed, table, or other device in which the electivelength of one or more supporting legs is to be varied.

It is an object of the present invention to provide a supporting leg fora device whose eiiective length can be adjusted to comparatively coarseand ine degrees.

Another object oi the invention is to provide an adjustable supportingleg ior a device adapted for both coarse and line adjust-ments and alsocapable of being positively locked in any adjusted position.

A further object of the invention is to provide a telescopic adjustablesupporting leg for a device whose members cannot be removedinadvertently from telescopic relation with respect to each other.

In its general aspects, the invention conteniplates a telescopicsupporting leg having cooperable clutch members which may be readilydisengaged from one another to permit movement of the telescopic memberswith respect to each other in effecting variations in the length of theleg structure. The clutch members may be engaged and held in positiveengagement in such manner as to prevent inadvertent change in theeffective length of the supporting leg. Moreover, with the clutchengaged, one of the leg members may be rotated with respect to the otherleg member to effect a fine adjustment. The parts have oooperableelements thereon, which will prevent inadvertent complete withdrawal ofone leg member from the other, thus insuring maintenance of their mutualtelescopic relation.

One form which the invention may assume is exemplied in the followingdescription and illustrated by way oi example in the accompanyingdrawings, in which:

Fig. 1 is a perspective view of a device embodying the invention.

Fig. 2 is a longitudinal section through one of the supporting legs ofthe device, with its parts in locked position.

Fig. 3 is a side elevation oi the supporting leg, with its parts inunlocked relation.

The invention has been particularly disclosed in the drawings as formingpart oi a scaffold unit S. It is to be understood, however, that it mayform part of other devices in which an adjustment of the effectivelength of the legs is desired.

As disclosed in Fig. l, a scafold is provided having vertical legs I0formng part of the end structures II and secured, as by welding, to alower cross member I2 disposed above the lower ends of the legs. Eachend structure of the scaiold may also include a diagonal brace I3, andthe end structures II themselves may be attached together by diagonalbraces I4 running from a lower cross member I2 on one structure to anupper cross member (not shown) on the opposite structure. A ladder orstairway I5 may also extend from the lower cross member I2 on onestructure II to the upper cross member on the other structure to assistin unifying the scatfold unit.

Each leg l0 includes an outer tubular upper member I6, which is securedto the cross member I2, and an inner lower member Il telescoped withinthe upper member, the lower member having an outside diametersubstantially equal to the inside diameter of the outer member, in orderto have a sliding telescopic ilt therewith. The lower end of the innermember Il may be provided with a suitable caster and caster mounting I8to facilitate movement of the scaiiold unit.

It is to be noted that the lower end of the outer tubular member I6 hasa plurality oi longitudinal slots I9, forming segments 2d which are bentoutwardly to impart an inherent tendency for the segments to expand awayfrom the inner leg member ll. A split or segmental nut 2| is welded, orotherwise secured, to the lower segmented end of the outer tubularmember I5 and has an upper tapered portion 22 inclined inwardly andupwardly. Actually, a solid nut may be welded to the lower end oi thetubular upright IS and the two members slotted to form the segments 20,2| which are bent outward slightly, in order that the nut 2l inherentlytends to disengage from the inner leg Il.

The inner leg Il is externally threaded for oooperation with theinternal thread on the split nut 2I. The major portion of the inner legis threaded, but its upper portion 23 remains unthreaded for a purposeto be described hereinafter. A collar 24 is disposed over the outer legI6, being movable downwardly into engagement with the split nut 2l tohold its segments firmly in engagement with the threads Ila of the innerleg and prevent disengagement of the nut therefrom because of itsinherent outward expansion tendency.

When adjustment of a leg I is desired, the collar 24 is moved upwardlyfrom engagement with the split nut 2|, which permits the latter toexpand outwardly slightly and remove its internal threads fromengagement with the eX- ternal threads Ila on the inner leg I7. The inner leg may then be moved upwardly or downwardly within the outer legmember i8 to adjust the eiective length of the leg structure, whereuponthe collar 2G is disposed over the split nut 2|, first engaging itsupper tapered surface 22 to force the nut back into threaded engagementwith the leg l1 and then moving over the outer cylindrical surface ofthe nut 2l in snug relation therewith, to prevent its disengagement fromthe leg member l?, thus securely locking the inner and outer leg membersil, i5 together. Downward movement ci the collar is limited byengagement of its shoulder 25 with the tapered nut portion 22.

By virtue of the telescopic movement of the inner leg member I7 Withinthe outer leg member l E, a rapid adjustment can be made in the eectivelength of the leg l). II a ner adjustment is required, the collar E isdisposed over the split nut 2 l, to cause its threaded engagement withthe inner leg Il, and the latter is then rotated in the properdirection, which produces its threading Within the split nut 2i and acorresponding alteration of the telescopic relation of the inner memberwithin the outer member, thereby7 modifying the eiTective length of theleg to a fine degree, depending upon the lead or pitch of the threads.

The major portion of the inner leg member l? is threaded, but its upperportion 23 remains unthreaded, so as to prevent complete unscrewing ofthe inner leg from the upper, outer leg member I6. It is apparent thatunthreading of the inner leg member within the split nut 2i eventuallyengages the lower end 23a of its unthreaded upper portion 23 with thenut, which precludes further rotation and unscrewing of the innermember. The unthreaded upper portion 23 of the inner leg has suiicientlength to provide a proper telescopic t with the outer member I8 andinsure appropriate support of the latter by the inner leg portionwithout lateral deilection.

When a plurality of legs l are used in a device, the effective length ofeach leg can be varied independently of the other legs. As disclosed inFig. l, the scaffold unit is disposed in such position that one pair oflegs I9 rests on a step 29 having a higher elevation than the support 2lfor the other pair of legs. rThe scaffold may be supported on such step26 and the other support 2l with all legs l0 in a vertical position bymerely shortening the eiective length oi one pair of legs on the step,or conversely, lengthening the eiective length of the other pair oflegs, as the case may be. A rapid adjustment may be made on any legthrough removing the retaining collar 24 from its encompassing positionon the split nut 2|, and telescoping the leg members I6, l1 with respectto each other, whereupon the collar 24 may be disposed over the nut tohold it in threaded engagement with the inner leg member I1, and a neadjustment made on any leg requiring such adjustment through rotatingthe inner leg member l1 with respect to the outer leg member i5. Anyother equipment of which the legs l il form a part may be similarlyadjusted.

It is, accordingly, apparent that a leg construction has been providedwhose eiective length can be adjusted quickly as well as to finedegrees. The construction is such that the parts are locked againstinadvertent movement from adjusted position, nor can the parts becompletely disengaged from one another unintentionally.

While I have shown the preferred form of my invention, it is to beunderstood that various changes may be made in its construction by thoseskilled in the art without departing from the spirit of the invention asdened in the appended claim.

Having thus described my invention, what claim and desire to secure byLetters Patent is:

A scaffold supporting leg comprising a vertical tubular outer supportingleg member terminating at its lower end in a plurality of downwardlyextending outwardly radially biased resilient fingers integraltherewith, an inner member telescopically received Within the outermember, said inner member having an upper cylindrical bearing portionengaging a complementary portion of said outer supporting leg member andhaving an externally threaded lower portion, a segmental internallythreaded nut xedly secured to said ngers for threaded engagement withthe threaded portion of the inner member when the ngers are forcedinwardly, and a collar on the outer member movable relative to the nutto force the ngers inwardly to place the nut into threaded engagementwith the threads of the inner member and to retain such engagement untilthe collar is moved relative to the nut to permit the lingers to moveradially outwardly, the length of the threaded portion on the innermember being substantially greater than the length or the threadedportion of the nut.

WALLACE J. S. JOHNSON.

REFERENCES CTED The following references are of record in the ie of thispatent:

UNITED STATES PATENTS Number Name Date 376,810 Brill Jan. 24, 1838411,481 Willson Sept. 24, 1889 1,197,727 Finkle Sept. 12, 1916 1,886,112Luarde Nov. 1, 1932 1,973,948 Fogelstrom Sept. 18, 1934 f 2,043,498Uecker June 9, 1936 2,256,892 Burman Sept. 23, 1941 2,327,050 KotlerAug. 17, 1943 2,388,179 ProWd Oct. 3G, 1945 FOREIGN PATENTS NumberCountry Date 976 Great Britain Jan. 23, 1885

